92 v6 electrical problems - Toyota Nation Forum : Toyota Car and Truck Forums

blulightandabat · 05-04-2011, 09:32 PM

ok so this truck whenever i change the alternator it kills the alt then the truck runs off the battery but shortly dies. she ate 2 already. anyone have any idea what this could be?

jetwhine · 05-05-2011, 05:27 AM

blulightandbat,

What was the original problem before you changed the first alternator?

blulightandabat · 05-05-2011, 08:10 AM

lack of power. i thought it was the alt cause it held no charge. changed battery too.

jetwhine · 05-05-2011, 07:19 PM

blulightandabat,

How long have you owned the rig? And how long have you had the problem?

blulightandabat · 05-06-2011, 12:46 AM

my uncles truck since new. it started about 7 years ago and parked after not being able to fix the problem. ive since found a love for toyotas and i want to fix if i can.

Quote:

Originally Posted by jetwhine

blulightandabat,

How long have you owned the rig? And how long have you had the problem?

sam333 · 05-06-2011, 11:52 PM

Are the diodes going bad in the alternators that have failed? If they are,
then you probably have a poor connection between the ( B+) terminal on the alternator and the positive side of the battery circuit. This will damage the diodes. A shorted battery charging light circiut will also damage diodes.

These truck are also notorious for bad connections from the plus side of the battery to the fuse/ relay block.

Use a multimeter to look for voltage across connections. Start the car and let it idle with a load on the alternator( lights , fan ,ect...). Go from the B+ terminal on the alternator to the positive battery post, you should have less than 0.2 volts showing on your meter. If you have more you have a bad connection. Go from the alternator case to the negative battery post, again look for less than 0.2 voltage, if you have more then you have a poor alternator ground.

Also never disconnect the battery while the engine is running ,it can damage the alternator.

arnaldo27 · 07-06-2011, 07:41 PM

Hello ,I have a problem with my 1990 4 runner the ac switch is blowing the fuse #18 when I replace the fuse work for maybe 10 minutes and blow the fuse again ,if some body know about this problem I need help